Sandwich toasters are well known, and can be found in many households and food establishments. The toasters are very convenient; they are portable, light and easy to use and they are faster than using a toaster oven. In recent years appliances were made which resemble a sandwich toaster but are used for baking cakes. These products bake waffles, muffins, donuts etc., quickly, but require constant supervision because the user does not know by looking at the cover of the appliance when the cake is ready. Furthermore, these appliances can become hazardous once they are turned on for long periods of time, because they become over-heated.
The compact size of this type of appliance dictates that its construction be well-suited to high heat temperatures applied directly to its interior surfaces, with exterior housing materials designed to withstand these heat levels and allow safe operation and handling of external parts such as the cover which opens to allow insertion of baking material, and control devices mounted on the cover.
Timer controllers are well-known in the art, and are typically provided by low-cost mechanical devices which operate on a spring provided as a thin elongated metal band wound in a flat coil configuration. These are based on a mainspring which uses a spiral torsion spring of metal ribbon—commonly spring steel, wound in a spiral. The winding mechanism uses a ratchet and pawl arrangement to prevent the spring from unwinding. When the spring is wound, thereby winding the flat coil with stored energy, this device automatically unwinds itself in accordance with a mechanically driven gear, to provide constant torque so that its release of spring energy can be controlled in accordance with a desired time cycle. Kitchen timers are typically based on these type of devices.
A problem with the use of these types of kitchen timers is the mainspring metal ribbon is subject to metal fatigue, which would tend to make it break or perform with reduced accuracy. Temperature is a factor in the proper operation of these devices, and excess temperatures can cause thermal distortion of the mainspring coil.
Due to the high heat levels of interior portions of the baking toaster appliances, it has not been considered possible to apply mainspring timer controllers to these appliances, as their operation would be adversely affected. Generally therefore, no low-cost mechanical timer controllers are available on these appliances and the problems associated with over/underbaking due to lack of supervision and control remain.
However, there are known small cooking appliances that do have a timer, such as a pizza maker. The pizza maker is distinguishable from a baking toaster, since the former has a round metal body which is not covered by an insulating housing. The body, as a result, is too hot for the touch when the appliance is operated, therefore it has a plastic handle for lifting and closing the cover. The timer is placed on the rear end of the plastic handle, because the handle is the only place on the pizza maker that a timer can function. On any other surface area of the pizza maker, a timer would become overheated and will malfunction. Because of its metal body, a pizza maker has less heat build-up internally, since the metal body enables heat dissipation to the external surrounding air.
Therefore, it would be desirable to overcome the disadvantages of prior art relating to baking toaster operation, due to lack of supervision and control.